The present invention relates to insulation of flat roofs and simultaneous construction of a gradient for positive drainage of the roofing placed on the insulation, the gradient being perpendicular to the outer edges of the roof and running in at least two directions perpendicularly to one another, and having between the differently angled gradients intersection lines comprising lines running from the corners of the roof towards the centre line of the roof, the insulation comprising rectangular elements arranged in rows parallel with the edges of the roof, each element having a sloping surface corresponding to the gradient of the roof and a greater thickness at two of the corners than at the two diametrically opposite corners, and adjusting elements of pyramidal shape arranged on top of the rectangular elements along the intersection lines, which pyramidal adjusting elements comprise two right-angled triangular side faces, the hypotenuse of which runs along the intersection line and and two other faces, which are narrow, acute triangles.
From U.S. Pat. No. 4,503,644 an arrangement and a system for creating a sloping roof out of a flat roof is known. Such an arrangement is often used on buildings which were originally constructed with a completely flat roof, and where in the centre of the roofing a drain for water was placed, the outlet being in the interior of the building. In connection with roof repairs, an insulation layer of slabs is placed on top of the original roofing, which slabs have not only been cut in such a way that they can cover the roofing area, but which are also cut in the shape of a wedge, making it possible to give the insulation, after it has been laid out, an even gradient towards the drain. In order to provide a uniform gradient, in which the intersection lines run from the corners of the roofing drain, an individual cutting of an essential part of the slabs forming the insulation layer is required. The individual cutting is costly, both in connection with the cutting process as well as during the placing, where it is necessary to make sure that the slabs are placed correctly and not mixed up. If one or more of the slabs are damaged during transport or during the placing, it will be complicated to get a replacement slab.
On account of the stricter rules recently introduced for work in connection with the laying out of insulation materials containing synthetic mineral fibres, the insulation materials should be of the kind not requiring adjustment at the site, where they are placed, or such an adjustment should at least be reduced to a minimum. These rules prevent any manual shaping or adjustment of standardized elements at the work site, as it is required in practice that the normal shaping should take place under controlled, industrial conditions, where effective precautions against undesirable dust can be taken.
It is the object of the present invention to provide a roof insulation where by means of a number of standardized elements an insulation layer with a gradient can be constructed without any cutting during the placing, the gradient running either from the centre of the roof against the edge or the other way round from the edge of the roof towards the centre to a drain. The number of different elements should be small, and the placing should be possible according to a simple and foreseeable system in order to avoid cutting of elements at the building site, but it should also be possible to replace damaged elements by adjusting standardized elements through simple shortening at right angles without any waste and without the use of dust-producing mechanical tools.
The object of the invention is met by means of an insulation, which is characteristic by the subject matter of the characterizing clause of claim 1. In addition to one or maybe two sets of rectangular elements, which can be put together for the formation of a gradient, only one special, triangular adjusting element will be needed for the formation of even roofing areas around the border lines between the roofing areas, and, if necessary, a plane infilling element to be place don top of the rectangular elements. There is in particular no need for cutting the rectangular elements along oblique lines and only a slight need for preceding marking of the elements. Thereby a great flexibility is ensured during the carrying out of the insulation work at the building site.
The simplest form of insulation is achieved according to a preferred embodiment of the invention when the rows in the two directions running perpendicularly to each other have the same width, and when the adjusting elements are in the shape of an isosceles triangle. According to this embodiment the border lines will run under an angle of 45.degree. in relation to the edges of the roof, which, when it is a question of rectangular buildings, often result sin a ridge or a valley in the middle of the roof. It is, however, possible also to use the insulation in connection with roofs whose gradient differs in the two directions running perpendicularly to each other. It is in particular advantageous to distribute the gradient of the rows in one of the directions on two sets of rectangular elements having the same dimensions as the elements in the rows running perpendicularly thereto, and also that the adjusting elements are isosceles triangles, the two sides of which are twice as long as the third one.